Friday 2010-12-10 Dev. video update and Discussion

[MD_Marx]

Well, if this colour is the result of computation alone, I think it is remarkable!
Fantastic modelling which just blows my engineering mind away.

If we are talking realism, I would say that a carburated Merlin engine starting up from cold will emit yellow flames because the mixture will be rich. After a few minutes, i would say the flame would go blu-ish?

A Daimler Benz of the period had fuel injection so i would imagine the exhausts would be blue-ish from the start as the air-fuel mixture would have been slightly leaner? Probably 'blipping' the throttle would make the burn 'leaner' as the blower increased the air flow, so it probably went bluer?

Are there any surviving RAF groundpersonnel (engine specialist) who would know? I might drop the Battle of Britain Memorial Flight a line... but it's almost a trivial detail, isn't it?

Can't wait for the game to come out, but I'd rather wait until Oleg is happy to release it, rather than rush it.

Marx

[334th_Gazoo]

These are my thoughts as a steel fabricator. Using an oxygen acetylene cutting torch as an example... A very rich mixture of gasses coming out of the torch is Orange with much Black smoke. A high oxygen mixture is Blue White.Setting the mixture At the optimal point between an Oxidising flame and Carburizing flame is ideal.

I believe that effciency in an engine may be measured thus, and exhaust coulor be matched accordingly.

Thankyou for your patience

334th_Gazoo

The point is.. Is it running Lean or Rich?

[WTE_Galway]

Carby mixture settings have nothing to do with the stack flames on startup.

Carburetor aircraft engines commonly have a hand priming pump like the one below out of a spitfire:



The pump injects fuel directly into the carb barrel or intake manifolds. Pumping it too many times before cranking the engine results in an excess of fuel and exhaust stack flames can result.

[Richie]

Originally Posted by 334th_Gazoo

These are my thoughts as a steel fabricator. Using an oxygen acetylene cutting torch as an example... A very rich mixture of gasses coming out of the torch is Orange with much Black smoke. A high oxygen mixture is Blue White.Setting the mixture At the optimal point between an Oxidising flame and Carburizing flame is ideal.

I believe that effciency in an engine may be measured thus, and exhaust coulor be matched accordingly.

Thankyou for your patience

334th_Gazoo

The point is.. Is it running Lean or Rich?

Right. If you look at all of the engines in the videos...in they dark... they're all blue. By the chart that was put up if the mixture is right and the engine is running perfectly the flame should be blue with a lick of red at the end. If you stood right up close maybe you could see some red.

http://www.youtube.com/watch?v=QhFAw...layer_embedded

http://www.youtube.com/watch?v=Xs_qt...layer_embedded

http://www.youtube.com/watch?v=4ZzvKCQwWj0

[pateador]

I've been working with planes and, at least in the case of radial engines, I still remember how amazed I was the first time I watched a ground test at night : the flames at full power are definitively white with a blueish end ( with the carburator and ignition tuned properly ) and they extended more than half the fuselage!!! ( the plane was a biplane used for cropdusting, with radial engine and one exhaust stub by the right side ) to give you and idea try to find pictures of Hurricanes used as night fighters... they had to add an anti-glare panel just ahead of the cockpit, and the streaking extends beyond the cockpit ...

[fireflyerz]

Again, very interesting flame patterns / colours on rpms on this meteor ...

http://www.youtube.com/watch?v=D7WS5...eature=related

Also interesting LACK of flame on this merlin, packard I presume, fuel types on both vids...who knows.

http://www.youtube.com/watch?v=-mQRJA5W8CI

[BadAim]

Wow, this thread is hilarious! The whole thing has been explained several times and still people argue about nothing. It makes me glad that I've decided to spend much less time here. See you on Friday, Oleg.

Originally Posted by fireflyerz

Again, very interesting flame patterns / colours on rpms on this meteor ...

Also interesting LACK of flame on this merlin, packard I presume, fuel types on both vids...who knows.

this is perfect example of a badly maintained RR (the former, whose owner/operator should be slapped in the face...repeatedly..with a big spanner...) and an engine who's heavily modified (that's Strega from the Reno Races) and maintained to perfection.

[JVM]

Originally Posted by Sternjaeger

this is perfect example of a badly maintained RR ...

Yes, sure, but keep in mind this a Meteor tank engine, derivated from a, but not a Merlin! So it is easy to imagine it was not that well maintained for a track vehicle use, that it may have had a much harsher life than an aero engine, and also the sparking system is different etc etc...
Besides it is running on a bench just for fun, driven by UK amateurs which are not swimming in money like the Strega people...

So please, a bit of moderation would not be out of place...

JV

[robtek]

One can clearly see that No.5 Cylinder on the left side and first No. 2, 3 and 4 then only No. 3 Cylinder on the right side have a different exhaust flame (red-orange vs blue-white).
Later the different exhaust temperatures are clearly seen.